Single electron gun time sharing oscilloscope



April 13, 1965 F. L. KATZMAN N 'SINGLE ELECTRON GUN TIME SHARINGOSCILLOSCOPE Filed Sept. 9, 1960 2 Sheets-Sheet l F fg.

FRED L. KATZMANN ATTORNEYS United States Patent O 3,173,606 SlNGlLEELECTRON GUN Thi/1E SHARENG @SCHLLSCGPE Fred L. Katzmann, Cedar lGrove,NJ., assigner to Fairchild Camera and instrument Corporation, Syosset,

NJY., a corporation oi Delaware Filed Sept. 9, 1960, Ser. No. 55,014 16Claims. (Cl. S15- 22) The present invention relates to time sharingoscilloscopes in which a cathode ray tube having a single electron gunis employed. A variety of waves are displayed on the face of the tube bymeans of switching from one wave to another and from one sweep speed toanother. Thus, the single electron beam is used to display differentwaves successively.

An objection to time sharing Oscilloscopes used heretofore is that inmany instances the trace of one wave was intense whereas that of theother was dim due to the fact that the electron beam slowly crossed thetube in one case, and rapidly crossed the tube in the other. In myinvention this disadvantage is eliminated since when switching from onesignal source to the other I provide means for simultaneously switchingfrom one bias level to another so that the bias of the grid or cathodeof the cathode ray tube is varied in accordance with the desired settingthereby making it possible to adjust the tube trace intensities to beequal, or to have other desired relationship. My invention althoughdescribed in copending application entitled Direct Read-Out System forOscilloscopes (in the name of Bernard L. 1i-legernan, Serial No. 34,124,filed une 6, 1960, and assigned to the assignee of this application), asapplicable to varying the intensity of index and readout dots relativeto a display is likewise applicable to those situations in which it isdesired that two completely unrelated electrical waveforms be displayedon the face of a single tube; to those situations where it is desirableto display a single waveform on dilerent time bases; or to the displayof diiierent waveforms on the same time base.

It is an object of this invention to produce two related or unrelatedelectrical waveform displays in time shared, alternate sequence on asingle gun oscilloscope, said displays being o varying amplitude and ondiierent time bases, the intensity of said displays being adjustable inany desired manner.

1t is another object of my invention to present a display wave to bemeasured alternately with a second display wave, which may tor examplebe a rectangular' wave to produce readout dots, the rst and seconddisplay waves being presented at adjustable relative intensities,adjustment being effected by prior adjustment of the bias level appliedto the control unit of the cathode ray tube according to the alternatepresentations of the two display waves (or display wave and readoutdots). It is understood of course that the waves are visiblesimultaneously on the cathode ray tube screen.

It is another object of the invention to blank the second or dotproducing display wave, i.e., reduce its intensity' to zero during thevertical and overshoot portions thereof in order to eliminate tails onthe dots.

lt is still another object of the invention to provide a single gunoscilloscope in which the intensities of related displays may beadjusted. Thus, if an electrical waveform is to be displayed on a giventime base, and a portion of that waveform is to be shown on an expandedscale in the second ot two presentations, this may be done and theportion selected produced with increased (or decreased) intensity in therst presentation. The portion to be enlarged can be picked out readilyfrom the first small scale presentation, and it will be known that thisparticular portion is the portion enlarged on the large scalepresentation.

Other objects and features of the invention will be clear when thefollowing description is considered in connection with the annexeddrawings in which,

FIGURE 1 is a block diagram of a single gun oscilloscope having twoswitches for alternately displaying two displays on the same tube, whileat the same time having those two displays in a correct intensityrelationship due to the provision of a third switch which switches thebias level of the cathode ray tube to produce the correct intensities;and

FiGURE 2 is a detailed schematic circuit of the means for adjusting therelative intensities of alternately displayed patterns, and the meansfor switching to produce these relative intensities alternately.

Referring now to FIGURE 1, 101 and 102 are independent and unrelateddisplay waves. Waves 101 and 102 are applied respectively to twopush-pull D.C. ampliers 103, 104l through input pairs of push-pullterminals 109, 110. Display waves 101, 102 are amplified by arnpliers103, 104 and are applied to pairs of output conductors 133, 143 and1334, 144 respectively. Synchronizing signals 147 and 14S having periodsdesignated T, t respectively, are derived from waves 101, 102 by wellknown differentiating circuits in amplifiers 103, 104 and are applied toinput conductors 153, 154 of synchronizing amplifiers 105, 106respectively.

Output conductors 145, 146 of ampliiers 105, 1116 are connected toconventional triggered sweep generators 107, 103 to generate sweep waves119, 120 with periods T, t respectively. Output conductors 135', 13e areconnected to a switch the arm 12S of which is usually placed in contactwith the conductor 135, 136 associated with the display wave 101, 102having the longest period T in order to synchronize a master clocksquare wave multivibrator 111.

The master clock 111 comprises a multivibrator which generates a pair ofout-o-phase square switching waves 112, 113, having a period 2T andapplies these to conductors 131, 132 respectively to connect theswitching Waves to the three switches 114, 115, 116.

Switch 114 is the vertical or Y-axis switch which is supplied with twopairs oi push-pull input signals from outputs 133, 143 and 134-, 144 ofpush-pull display wave amplifiers in channels A and B respectively.

Thus, displays 101, 102 are caused to appear alternately andrepetitively at push-pull output conductors 151, 152 by the coaction ofswitch waves 112 and 113, which are applied to grids 183 and 184 also,where they cause anodes 13S and 1% of triodes 131 and 182 to alternateoppositely in potential level. The input conductors 191 and 192 topush-pull amplifier 123 are connected to anodes 18S and 156 and thusreceive biases determined by the adjustment of potentiometer 137 whichcontrols the anode currents through resistors 187 and 18S when grid 183or 184 is made positive. rThis action occurs at the rate of 1/2T timesper second. This alternating bias is for the purpose of trace separationbetween the displays from channels A and B, which displays also occuralternately and repetitively at l/zT times per second.

Thus, when signals over channel B are being transmitted to the vertical(Y-axis) push-pull DC. amplifier 123 to produce deflection waves 102 atvertical plates 121, 122, plate 121 is biased positively with respect toplate 122 and when signals over channel A are being transmitted plate122 is biased positively with respect to 121. As a result, the displays101 and 102 are shifted on tube face 100 relative to each other. Theamount of shift depends on the adjustment of 137.

Each of sweep generators 107, 108 has at least three jr t aisanceoutputs. These are respectively: linear time base sweep waves H9, 5.3.5'on conductors 39, *130; positive going brightness waves 1.6i, 362 onconductors i559, 25d; and negative going blanking waves M7, M3 onconductors iii, iii. rThe sweep waves H?, are applied to the c (X-axis)switch i5, and the brightness waves tel, to2 and blanking waves M7, 11%are applied to the i (Z-axis) switch le.

Coaction between the various waves generated in channels A and B, andthe master clock switch wave outputs M2, M3 at the three switches iid,M5, tio, pro duces alternate and repetitive displays of waves Milt, En?.on tube face we. Two successive displays occur with a periodicity 2T,each display occupying a portion of time interval T. Each display isbrightened during the trace time of its respective sweep wave, andblanked during the retrace and dead time of that sweep wave. Thedisplays may be superposed or separated verticaliy by adjustment 37; or,horizontally, by the customary sync phase control led of sweep generator98, in the usual manner for triggered sweep generators; or both.

Referring now to FGURE 2, an arrangement is shown illustrating anotheruse of my invention. Display wave 299 of period T has a section S whichit is desired to examine in detail while (at the same time) examining29d. Wave 2d@ is applied to both pairs of terminals liti?, M0. Switcharm 65 disconnects sweep generator i523 from normal sync output idd (secalso PEG. l) and connects it to output le@ of sweep generator 167 inorder to synchronize te@ with the 1M sweep instead of with the displaywave 209. This is in preparation for a delayed sweep observation.

This type of operation wherein a delayed portion of `a sweep is used toinitiate a second, or delayed, sweep is well known in the art, onemethod of such initiation being described in US. Patent No. 2,825,848,in the name of R. F. Casey.

A delaying sweep switch 173 is provided on sweep generator 167. Thisswitch when operated causes sweep wave 2319 to act as a celaying sweepin the manner described in detail in the above-mentioned Casey patent.in brief a synchronizing signal is erived from a portion S of wave 2129and applied through potentiometer 69, conductor 164, and switch arm 16Sto sweep generator 10S.

As in the Casey patent adjustment 'of potentiometer 169 determines thestarting point 292 at which sweep generator 10S is triggered andadjustment of 2ti3 determines the termination of sweep wave 22dgenerated by sweep generator MBS at a time such as 264. The duration Sof sweep wave 22@ thus is made to correspond to a desired portion S ofsweep wave 21W.

In order to produce the two separate but related displays 200, 2M ontube face the, where display 291 is an expanded view of the brightenedportion S ot display 26o, the display wave 2%@ is ampiied in amplitiers15G, 104 and applied over output conductor pairs 133, 143 and 134, 144to the input of the V switch it@ as described above for FIGURE 1. At thesame time the delaying sweep 29 and the delayed sweep 220 are applied tothe input of the H switch 215.

The V switch and the H switch are controlled by switch waves 212, M3 tocause the display wave to be displayed on two time bases, namely theregular sweep 219 and the delayed sweep 229.

At the time when the positive going portion 221,4 of switch wave 212 isapplied to the V switch and the H switch and to the anode of diode 221to make cathode follower tube 2&5 conductive in the I (intensity) switchstructure 11.6, the negative portion 2F11 of switch wave 213 is appliedto the anode of diode 222. Thus, no positive potential is applied togrid 2% of cathode follower 2% at this time. The cathode followerremains in a cut-off condition due to positive bias developed on cathoderesistor 23@ by the positive wave peal; 2id on gri 267'. Thus, allpotentials from diodes 224, 226, 228 are ineffective to produce outputsat 239 for transmission on conductor 179 for application to cathode raytube T25 (FIGURE l) and these potentials cannot modulate the cathode raytube beam 271 during the first half cycle time T orf switch wave 212.

During this same time, however, a positive bias from potentiometer 229is applied to the anode of diode 227 and is applied to grid 297 and bycathode follower action of tube 295 controls the intensity level of beam3.7i. This type of intensity gate is described in a copendingapplication by Fred L. Katzmann, Serial No. 800,337, now Patent No.2,997,620, assigned to the same assignee.

Switch 73 also causes a brightening wave 174, of duration S, insynchronism with T but shorter than T', to be applied to the anode ofdiode 223 via output conductor 159. Positive portions of brighteningWave 174 are applied to grid 2ti7 and appear on conductor 17d-and grid28 to increase the beam Itl and intensify the portion S of display 2G@on tube face We. A blanking wave 175, of dure.- tion B, corresponding tothe retrace and dead-time of sweep wave 219 may be applied to thecathode of diode 22S, if desired, to cut-oft beam 171 during the retraceand dead time of sweep wave 2l?.

Nlien the positive going portion 215 of switch wave 2i3 is applied tothe anode of diode 222, tube 286 becomes conductive and 2555 becomesnon-conductive. Thus, the brightening, blanlting and bias potentialsassociated with amep 22h are applied to control the intensity of beam i,when sweep 220 is switched to the H deflection plates i231, 124 in piaceof sweep 29 by the heretofore described action of the H switch M5.During the second half period 2liot the wave ZLZ, the intensity signalsapplied to grid 267 are made ineffective by cut-01T laction on cathodefollower 265.

it will be clear to those skilled in the art that dot producing wavesand their associated brightening, blanking and bias potential may beapplied to the H, V and I switches, as described in Patent No. 2,997,620referred to above, or any other waves related or unrelated to displaywaves i d or 206i as described herein may, by means or a multi-contactswitch, be selected and applied to the H, V and switches, to produce avariety of displays.

F or example, when a display wave 200 is to be measured quantitativelyby means of read-out dots on an oscilloscope equipped with a directread-out system switch, the display wave 2d@ is displayed with the dots270, 271 instead of with the expanded section 29T.. To accomplish this,the switch arms 243, 244, 247, 248, 249 of the system switch aremanualiy and simultaneously placed in positions indicated as 26? inFGURE 2.

When the switch arm are in this position a vertical readout wave V andits base level are applied to the V-switch arms 243, 24d respectively,and a horizontal read-out wave H with its base level is applied toH-switch arm 247. These waves are generated in generator 241 which maybe of the type shown at 49d in copending application Serial No. 34,124.

A free running unsymrnetrical multivibrator 24) which produces an outputpulse 259, at a mean frequency of '7de cycles for example as shown at403 in the above copending application, synchronizes generator 241 at383 cycles. The pulse width of waves 250 is made adequate to include therapidly moving portions 257 of the readout waves. Waves 25? are appliedto switch arm 248 and provide beam blanliing during the rapidly movingtails between the dots.

`While I have described preferred embodiments of my invention it will beunderstood that many modifications and variations are possible. I wishtherefore to be limited not by the foregoing description but solely bythe claim granted to me.

What is claimed is:

1. in a display device having elements to produce a atrasos single lightspot, in combination, means for applying rst and second deliectingfields of different frequencies to deilect said spot in a lirstdirection, means for applying a field to deflect said spot in a seconddirection, rst switch means for alternately applying said irst andsecond fields, thereby to develop two independent traces in time sharingsequence; second switch means to adjust the intensity of the spot toeither of two selected constant levels throughout a trace interval; andmeans for actuating said two switch means in synchronism, whereby theintensity of said spot throughout one `trace may be adjustedindependently of the intensity of the spot throughout the other trace.

2. ln a cathode ray oscilloscope having a single cathode ray tube withat least one electron beam, in combination, two beam dellecting meansfor producing a two dimensional display, means to alternately apply twodeilection waves of diierent frequencies to one of said beam deflectingmeans, means 'to alternately apply two corresponding derlection waves ofdifferent frequencies to the other of said beam deflecting means, meansto derive beam intensifying waves synchronous with the i'irst and secondof said deflection waves, means to apply said derived waves to intensifythe electron beam, and switch means to simultaneously effect saidalternate application of deection waves to said one and said otherdetlecting means and the alternate application of said derived waves tointensify said beam.

3. ln a cathode ray oscilloscope having at least one electron beam witha control electr-ode therefor and first and second beam deection meansfor developing elds substantially at right angles to one another, incombination, means for applying lirst and second waveforms to bedisplayed alternately to the irst deflection means for alternatelyproducing two rst fields, two corresponding sweep generators forapplying sweep waves to the second deflection means for alternatelyproducing two second fields, means `to derive corresponding beamintensity controlling waves synchronous with said irst land secondwaveforms, means to apply said intensity controlling waves to thecontrol electrode to intensify the beam, and switch means to switch saidcorresponding display waveforms, sweep waves and intensity controllingwaves simultaneously to said iirst and second deflection means and thecontrol electrode, respectively.

4. In a cathode ray oscilloscope having a cathode ray tube including afluorescent screen, at least one electron beam source and means fordeilecting the beam in two directions; in combination, means forapplying an electrical waveform to be analyzed to one of said deflectionmeans and a second electrical waveform to the other of said meanssimultaneously to form a pattern on said screen; means to bias the beamat two intensity levels; means for generating two dot producing signals,means t-o apply said signals simultaneously to said deilecting meansalternately with said pattern, means to modify said two dot producingsignals individually to position the generated dots at selected pointson said screen with respect to said waveform display Vand means toindicate the amount of modilication of said dot producing signals tothereby indicate on one of two indicating means one coordinate dimensionfrom one of said dots to the other and on the other of said twoindicating means the other coordinate dimension from said one ot saiddots to the other thereof, and means to apply one of said intensitylevels to bias said beam when said dots are displayed, and the other ofsaid levels to bias said beam when said pattern is displayed.

5. In a cathode ray oscilloscope having a cathode ray tube including alluorescent screen, a single electron beam source and t-he means fordellecting the beam in two directions; in combination; means forapplying an electrical waveform to be analyzed to one of said deflectionmeans and a second electrical waveform to the other of said deflectionmeans simultaneously to form a pattern on said screen; means forgenerating two dot producing signals;

means to apply said signals to said deection means; means to adjust theintensity of the electron beam to at least a. `rst and a second level,switching means for applying said dot producing signals alternately withthe pattern producing signals to said vdeilection means and means forsimul- Itaneously adjusting said intensity at said first level when saiddots are produced and at said second level when said pattern isproduced; means to modify said two dot producing signals individually toposition the generated dots at selected points on said screen ywithrespect to said wave- -form display; means to indicate the amount ofmodication of said dot producing signals individually .to therebyindicate on one of two indicating means one coordinate distance `fromone of said dots to the other and on the other of said two indicatingmeans the other coordinate distance from one of said dots to the otherthereof; and means to position said waveform display together with saiddots with respect to the tube screen.

6. In a cathode ray oscilloscope having a cathode ray tube including afluorescent screen, a single electron beam source and t-he means fordellecting the beam in two directions; in combination; means forapplying an electrical waveform to be analyzed to one of said deflectionmeans and a second electrical waveform to the other of said deflectionmeans simultaneously to form a pattern on said screen; means forgenerating two dot producing signals; means to apply said signals tosaid dellection means; means to adjust the intensity of the electronbeam to at least a lfirst and a second level, switching means forapplying said dot producing signals alternately with the patternproducing signals to said deilection means and means for simultaneouslyadjusting said intensity at said iirst level when said dots are producedand at said second level when said pattern is produced; means to modifysaid two dot producing signals individually to position the generateddots at selected points on said screen with respect to said waveformdisplay; and means to indicate the amount of modification of said dotproducing signals individually t0 thereby indicate on one of twoindicating means one coordinate distance r-om one of said dots to theother and on t-he other ot said two indicating means the othercoordinate distance from one of said dots to the other thereof.

7. In a cathode ray oscilloscope having a cathode ray tube including alluorescent screen, at least one electron beam source and means fordeflecting the electron beam in two directions; in combination; meansfor simultaneously applying an electrical waveform to be analyzed to onedeiiection means and a second electrical waveform to the other deectionmeans to form a pattern on said screen; means to apply at least twointensity levels to the electron beam; means to apply one of saidintensity levels to said electron beam when said pattern is formed onsaid screen; means to produce a pair of phase related rectangularelectrical waves of the same frequency; means to adjust the base leveland amplitude of said waves individually; means `for simultaneouslyapplying one of said adjusted rectangular waves to one deflection meansand the second of said rectangular wav-es to the other dellection meansto thereby produce two dots on said screen; the position of one of saiddots depending upon the base levels of said waves and the position ofthe second of said dots depending upon the base levels and amplitudes ofsaid waves; means to apply ano-ther of said intensity levels to saidbeam simultaneously with the application or" said rectangular waves; andmeans to indicate the settings of said adjustment means to therebydirectly indicate the position of said other dot with respect to saidone dot.

8. In a cathode ray oscilloscope Ihaving at least one electron beam anda lluorescent screen; in combination, first means to deflect the beam,second means to deflect the beam at right angles to said first means,means to control fthe beam intensity; means to generate a plurality ofdisplay producing waves for application to said lirst means; means forproducing a plurality of sweep waves for application to said secondmeans; means to derive a plurality of beam intensity controlling wavesfrom said display prosnr/aces ducing waves for application to saidintensity control means; display switch means -to select a pair fromamong the plurality of display producing waves, a pair from among theplurality of sweep waves and a pair from among the plurality of beamintensity controlling waves; and electronic switch meansiorsirnultaneously applying one of each of said selected pairs of wavesto said first means, said second means, and said beam intensity controlmeans, to alternately produce selected time sharing pairs o-f displaysat selected intensity levels.

9. in a cathode ray Ioscilloscope lhaving at least one electron beam anda iluorescent screen; in combination, irst means to deilect the beam,second means to deilect the beam at right angles to` said first means,means to control the beam intensity; means to generate a plurality ofdisplay producing `Waves for application to said iirst means; means forproducing a corresponding plurality of sweep waves` in Vsynchronism witheach of said plurality of display producing waves respectively forapplication to said second means; means to derive a plurality of lbeamintensity controlling waves from said display producing waves forapplication to` said intensity control means; display switch means toselect a pair from among the plurality of display producing waves, apair from among the plurality of sweep waves and a pair from among theplurality of beam intensity controlling waves; and electronic switchmeans for simultaneously applying one or" each of said sclected pairs ofwaves to said first means, said second means, and said beam intensitycontrol means, to alternately produce selected time sharing pairs ofdisplays at selected intensity levels.

l). in a cathode ray oscilloscope having at least one electron beam anda fluorescent screen; in combination; first means to deflect the beam;second means to deilect the beam at right tangles to said first means;means to control the beam intensity; means to apply a display waveformto said first means; means for producing a sweep wave of desiredduration and applying said sweep wave to said second means at apredetermined time relative to said display Waveform; means to produce adelayed sweep wave iof a predetermined amplitude, said delayed sweepwave being initiated subsequently to said predetermined time and beingof a duration shorter than said duration of said iirst sweep wave; meansfor apply= ing said delayed sweep wave to said second means; means forderiving an intensity wave simultaneous in time with said delayed sweepwave; means for generating iirst and second blanking waves insynchronism with said rst sweep wave and said delayed sweep waverespectively; means for applying said intensity and blanking waves tosaid intensity control means; and electronic switch means forsimultaneously applying said display waveform, said tirst sweep wave,said intensity Wave and said first blanking wave to said yhrst means,said second means, and said beam intensity control means, respectively,and for alternately applying said display waveform, said delayed sweepwave, and said second blanking wave to said rst means, said secondmeans, and said intensity control means respectively to thereby maltevisible simultaneously ra display waveform with a portion intensied andthe same display waveform with said intensilied portion ex* panded.

ll. In a cathode ray oscilloscope having at least one electron beam anda fluorescent screen; in combination, rst means to deflect the beam;second means to difterently deflect the beam; means to intensify thebeam; means to amplify display waves including a display Waveform, arelated portion of that waveform, an unrelated waveform, and adot-producing square wave, and for applying said display waves to saidirst means; means to generate a sweep wave synchronous with each of saiddisplay waves; means for deriving lanlcing waves from each said displaywave at a Selected amplitude; means for applying said blanking waves tosaid beam intensity ing means; display switch means to select a pairfrom among said display waves, a corresponding pair from among saidsweep waves, and at least one from among said blanking waves; andelectronic switch means actuated synchronously vwith one of said pair ofdisplay waves for simultaneously applying one of each of said selectedpairs of waves to said first means and said second means, and forapplying at least said one of said blanking Waves to said beamintensifying means alternately, to thereby produce alternately aselected pair of patterns with portions at selected intensity levels.

12. In a cathode ray oscilloscope having at lcast one electron beam anda iiuclrescent screen; in combination, iirst means to deflect the beam;second means to deflect the beam at right angles to seid first mcans;means to control the beam intensity; means to amplify a plurality ofdisplay waveforms for application to said first means; means to apply apredetermined DC. component to each said amplified waveform; means forproducing a corre spending plurality of sweep waves each in synchronismwith said display `lviaveforms for application to said second means;means to derive a plurality of beam intensity controlling waves fromsaid display waveforms for application to said intensity control means;display switch means to select a pair from among the plurality of ampleddisplay waveforms having D.C. components, to select a corresponding pairfrom among the plurality of sweep waves and to select a pair from amongthe plurality of beam intensity controlling waves; and electronic switchmeans for simultaneously applying one of each of said selected pairs ofwaves to said first means, said second means, and said beam intensitycontrol means alternately, to thereby alternately produce selected timesharing pairs of separated displays at selected intensity levels on theiiuorescent screen.

13. In a cathode ray oscilloscope having at least one electron beam anda tiuorescent screen; in Combination, lirst means to deilect the beam;second means to deflect the beam at right angles to said tirst means;means to control the beam intensity; means to amplify a displaywaveform; means for producing a sweep wave of desired duration andapplying said sweep wave to said second means at a predetermined timerelative to said display waveform; means to produce .a delayed sweepwave of a predetermined amplitude, said delayed sweep wave beinginitiated subsequently to said predetermined time and being of aduration shorter than said duration of said rst sweep wave; means forapplying said delayed sweep wave to said second means; means forderiving an intensity wave simultaneous in time with said delayed sweepwave; means for generating first and second blanking waves insynchronism with said tirst sweep wave and said delayed sweep waverespectively; means for applying both said intensity and blanking wavesto said intensity control means; means to generate a square wave with apositive portion having the same duration as said sweep wave and anegative portion having said duration; means to mix said displaywaveform and said square wave to produce mixed waves for application tosaid iirst beam deiiection means; means for applying said mixed waves tosaid first deecting means; and electronic switch means actuated by saidsquare Wave for simultaneously applying said mixed waves, said firstsweep wave, both said intensity wave and iirst blanking wave to saidiirst means, said second means, and said beam intensity control means,respectively, and for alternately applying said mixed waves; saiddelayed sweep wave, and said second blanking wave to said first means,said second means, and said intensity control means respectively tothereby make visible simultaneously a display waveform with a portionintensiiied and the same display waveform with said intensiiied portionexpanded and separated from said display waveform.

i4. ln a cathode ray oscilloscope having at least one electron beam anda fluorescent screen; in combination; a iirst means to deiiect the beamand a second means to `deflect the beam; means to intensify the beam;means to amplify a display waveform with a first period and a displaywaveform with a second period; means to generate rectangular waves witha period twice that of said first period; means for mixing said displaywaveforms and said rectangular waves to produce first and second mixedwaves for application to said first means; means to generate sweep wavessynchronized with said first and second periods for application to saidsecond means; means to derive iirst intensity controlling waves fromsaid first period display waveforms and second intensity controllingwaves from said second period display waveforms for application to saidintensifying means; first, second, and third electronic switch meansoperated in synchronism by said rectangular waves for applyingsimultaneously said first mixed waves, said sweep waves of said firstperiod, and said first intensity controlling waves to said firstdetiecting means, said second deflecting means, and said intensifyingmeans, respectively, and alternately applying said second mixed waves,said sweep waves of said second period, and said second intensitycontrolling waves to said first deecting means, said second defiectingmeans and said intensifying means, respectively, whereby alternate andunrelated two dimensional display patterns are produced on thefluorescent screen in time shared sequence, said display patterns beingspaced apart in one dimension.

15. In a cathode ray oscilloscope having a cathode ray tube including afluorescent screen, at least one electron beam source and means fordeflecting the electron beam in two directions; in combination; meansfor simultaneously applying an electrical waveform -to be analyzed toone deflection means and a second electrical waveform t-o the otherdeflection means to form a pattern on said screen; means to apply atleast two intensity levels to the electron beam; means to apply one ofsaid intensity levels to said electron beam when said pattern is formedon said screen; means to produce a pair of phase related rectangularelectrical waves of the same frequency which rests alternately at a baselevel and at an amplitude level and which has rapidly moving portionsbetween said levels; means for simultaneously applying one of saidrectangular waves to one deflection means andthe second of saidrectangular waves to the other deflection means to thereby produce twodots on said screen; the position of one of said dots depending upon thebase levels of said waves and the position of the second of said dotsdepending upon the base levels and amplitude levels of said waves; meansto derive a blanking wave corresponding in time with said rapidly movingportions of said rectangular waves; and means to apply another of saidintensity levels and said blanking wave to said beam simultaneously withthe application of said rectangular waves to thereby make said beamtrace invisible between said dots.

16. In a cathode ray oscilloscope having a cathode ray tube including afluorescent screen, at least one electron beam source and means fordeliecting the electron beam in two directions; in combination; meansfor simultaneously applying an electrical waveform to be analyzed to onedeflection means and a second electrical waveform to the otherdeflection means to form a pattern on said screen; means to apply atleast two intensity levels to the electron beam; means to apply one ofsaid intensity levels to said electron beam when said pattern is formedon said screen; means to produce a pair of phase related rectanguiarelectrical waves of the same frequency which rests alternately at a baselevel and at an amplitude level and which has rapidly moving portionsbetween said levels; means to adjust the base levels and amplitudelevels of said waves individually; means for simultaneously applying oneof said adjusted rectangular waves to one deflection means and thesecond of said adjusted rectangular waves to the other defiection meansto thereby produce two dots on said screen; the position of one of saiddots depending upon the base levels of said waves and the position ofthe second of said dots depending upon the base levels and amplitudelevels of said waves; means to derive a blanking wave corresponding intime with said rapidly moving portions of said rectangular waves; meansto apply another of said intensity levels and said blanking wave to saidbeam simultaneously with the application of said rectangular waves tothereby make said beam trace invisible between said dots; and means toindicate the settings of said adjustment means to thereby directlyindicate the position of said other dot with respect to said one dot.

References Cited by the Examiner UNITED STATES PATENTS 2,313,967 3/43Read 314-22 2,407,898 9/ 46 Norgaard 315-22 2,418,133 4/47 Miller etal315-22 2,483,140 9/49 Higham 315-22 2,492,700 1 2/ 49 Jeanne 315-222,547,289 4/51 Smart 315-22 2,620,455 12/52 Fockler 315-22 2,625,6671/53 Chance 315-22 2,739,264 3/ 56 Shreve et al. 315-22 2,830,227 4/ 5 8Hasbrook 315-22 2,858,475 10/58 Blake 315-26 2,860,284 11/58 McKim315-22 OTHER REFERENCES Heins van der Ven: Testing Amplifier OutputValves by Means of the Cathode Ray Tube, Philips Technical Review, vol.5, No. 3, March 1940, pp. 61-64.

DAVID G. REDINBAUGH, Primary Examiner.

RALPH G. NILSON, ROY LAKE, Examiners.

1. IN A DISPLAY DEVICE HAVING ELEMENTS TO PRODUCE A SINGLE LIGHT SPOT,IN COMBINATION, MEANS FOR APPLYING FIRST AND SECOND DEFLECTING FIELDS OFDIFFERENT FREQUENCIES TO DEFLECT SAID SPOT IN A FIRST DIRECTION, MEANSFOR APPLYING A FIELD TO DEFLECT SAID SPOT IN A SECOND DIRECTION, FIRSTSWITCH MEANS FOR ALTERNATELY APPLYING SAID FIRST AND SECOND FIELDS,THEREBY TO DEVELOP TWO INDEPENDENT TRACES IN TIME SHARING SEQUENCE;SECOND SWITCHES MEANS TO ADJUST THE INTENSITY OF THE SPOT TO EITHER OFTWO SELECTED CONSTANT LEVELS THROUGHOUT A TRACE INTERVALS; AND MEANS FORACTUATING SAID TWO SWITHCH MEANS IN SYNCHRONISM, WHEREBY THE INTENSITYOF SAID SPOT THROUGHOUT ONE TRACE MAY BE ADJUSTED INDEPEND-